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(No Model. 2 Sheets-Sheet 1.

A. J. NELLIS.

. PORTABLE ELECTRIC ABRADING' DEVICE.

Patented May 9, 1893 wimmow I m5 mmms PETERS co, Mow-Limovv uwswmsmw. o c.

(No Model.) 2 SheetsSheet 2.

A. J. NELLI PORTABLE ELECTRIC ABBA DEVICE.

No. 497,197. Patented May 9,1893.

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UNITED STATES PATENT OFFICE.

AARON J. NELLIS, OF PITTSBURG, PENNSYLVANIA.

PORTABLE ELECTRIC ABRADING DEVICE.

SPECIFICATION forming part of Letters Patent No. 497,197, dated May 9, 1893.

Application filed December 12, 1892- Serial No. 454,924. (No model.)

To all whom it may concern:

Be it known that I, AARON J. NELLIs, of Pittsburg, county of Allegheny, and State of Pennsylvania, have invented a new and useful Improvement in Portable Electric Abrading Devices, of which the following is a specification.

The object of my invention is to provide a compact device of simple construction which may be used for planing, grinding, abrading, or polishing surfaces and which may be readily moved over the surface in order that every part of the same may be acted upon.

My invention consists of a power driven portable device embodying an electric motor arranged to be moved bodily over the surface to be treated and constructed to operate a rotary tool in contact with the said surface.

The invention also consists in the details of construction and combination of parts hereinafter described and claimed.

In the accompanying drawings,-Figure 1, is a vertical section through my improved de vice. Fig. 2, is a top plan view of the same. Fig. 3, is a horizontal section on the line 33 of Fig. 1.

Referring to the drawings,-A represents a bell shaped frame or casting which is adapted to receive and sustain the operative parts of the device hereinafter described. This frame is provided with legs a, which have journaled in their ends rollers a which are adapted to move over the surface during the operation of the device and afford a support for the same.

B represents an electric motor, consisting as usual of the stationary field magnets b, and the armature 11' carrying the vertical motor shaft If. The armature is preferably of the form, known as the Gramme ring and the fields are mounted within the frame so as to be capable of a limited movement vertically, this result being accomplished by providing the interior of the frame at intervals with plates 0 having vertical grooves therein which are adapted to receive the vertical ribs 0 projecting from the plates 0 fixed to the field magnets.

D represents a cutting, grinding, abrading or polishing tool, which may be of any appropriate form and which is represented in the present case as consistin of a horizontal disk at, removably attached to the lower end of the motor shaft by means of a pin (1, and having on its under surface a series of cutting points (1 which when the shaft is rotated are adapted to act on the surface to be ground. It is however to be understood that the machine is not to be limited in use to any particular purpose; that it may be used for producing plane surfaces on glass, stone, or other material by planing, grinding, or abrasiomor for smoothing or polishing plane surfaces produced by this or other machines; and that while the drawings show a cutting tool on the rotary shaft this may be replaced by another having a grinding, abrading, or polishing surface, according to the work to be done.

In order that the field magnets may be moved vertically between the guides to the end that the tool may be adjusted with relation to the rollers carried by the frame so as to act under a greater or less degree of pressure according as the nature of the surface to be treated may require, 1 provide a vertical threaded shaft E which is screwed into astationary interiorly threaded sleeve 6, mounted rigidly in the upper part of the frame. This shaft is provided near its lower end with a groove into which project two semi-circular ribs extending from the inner sides of lugs F, forming jointly a bearing for the shaft, and which are fixed rigidly to the field magnet as shown. The upper end of the shaft is provided with a crank f by the rotation of which the field magnets will be moved verticallybetween the guides of the frame and thereby adjust the tool carried by the motor shaft farther from or nearer to the surface acted on as the case may be.

In order that the frame may be conveniently grasped for the purpose of moving the device over the surface, I surround the same with a circular handle II in the form of an ordinary commercial gas pipe, which is sustained at intervals by brackets or lugs 7L projecting outward from the frame.

In operating the device the current from any suitable source is supplied through conductors I, and the motor shaft carrying the tool causes it to rotate at a high rate of speed. The circular handle is then grasped and the frame moved bodily over the surface with the rollers in contact therewith, and the tool acting thereon.

Owing to the high rate of speed given to the tool and the fact that the device may be moved readily and freely over every part of the surface it has been found that the surface can be effectually and quickly planed or ground and a high degree of finish imparted to the same.

Having thus described my invention, what I claim is- 1. In a machine of the character described the combination of a portable, self-sustaining frame, a vertical shaft rotatively supported. therein, a rotary surfacing tool fixed on the lower-end of the shaft, means for adjusting the shaft in the direction of the length of its axis and for sustaining it in adjusted position, and a motor for driving the shaft; whereby the apparatus is adapted to be moved over the surface to be operated on, and the tool to be rotated in a constant plane.

2. In a machine of the character described the combination of a portable, self-sustaining f rame,a shaft rotatively mounted therein with its axis at right angles to the base, means for adjustingtheshaft in the direction of its length and adapted to sustain it in adjusted position, a rotary tool fixed on the end of the shaft, and an electric motor sustained in fixed relation to the shaft, whereby the tool is adapted 4. In a device of the type described, the

combination of the bell shaped frame pro vided with the depending legs, the rollers j ournaled in the lower ends of said legs, the guides on the interior of the frame the motor mounted between said guides and having its shaft adapted to receive an abrading tool, the vertical threaded shaft, the fixed threaded collar within which the shaft is screwed, the hearing on the motor within which the lower end of the shaft is loosely mounted and the crank applied to the upper end of said shaft.

In testimony whereof I hereunto set my hand, this 1st day of December, 1892, in the presence of two attesting witnesses.

AARON J. NELLIS. Witnesses:

Rojer. C. NIonioL, E. S. Cones. 

